1. Field of the Invention
The present invention relates to an optical element which is used for a solid-state light-emitting element utilizing electroluminescence (EL) and to a light-emitting device including the optical element. The present invention also relates to a lighting device including the light-emitting device. In addition, the present invention relates to a method for manufacturing the optical element.
2. Description of the Related Art
An organic EL element which is an example of the solid-state light-emitting element (also referred to as a light-emitting element) has been actively researched and developed. In the fundamental structure of an organic EL element, a light-emitting organic compound is sandwiched between a pair of electrodes. By applying voltage to this element, light emission from the light-emitting organic compound can be obtained.
The organic EL element can be formed into a film shape and thus a large-area element can be easily formed. Therefore, utility value of the organic EL element as a planar light source that can be applied to lighting or the like is also high.
As described above, application of an organic EL element to light-emitting devices, lighting devices, or the like is expected. In Patent Document 1, an organic optical device including an organic thin film transistor and an organic EL element is disclosed.